Information technology (IT) managers face a number of challenges as they are increasingly pushed to improve service delivery while lowering operational costs. These challenges include decreasing “server sprawl”, improving system utilization, reducing system management complexity, and improving the flexibility of IT resources. To address these challenges, many IT organizations are implementing some form of hardware virtualization or server virtualization.
Conventional servers consist of three major components: a central processing unit and its associated temporary data storage, a data storage unit for long-term data retention, and an interface to a network. In a conventional server, these three components are physically connected to each other in a single device.
Hardware virtualization allows virtual servers to be built by combining various components indirectly through a control server or computing fabric. The components in a virtual server typically include a stateless server consisting of a central processing unit and its associated temporary data storage, a data storage unit for long-term data retention, and an interface to a network. These components will be referred to herein as the processing server, the disk, and the network interface, respectively.
To create a virtual server, appropriate components for a desired server configuration are chosen from a pool of processing servers, a pool of disks, and a pool of network interfaces. The selected components are connected to the control server rather than directly to each other. Software in the control server keeps track of which components are connected in this manner and handles communication among the components. The software might also allow an administrator to remotely monitor and control a virtual server using either a command line interface or a browser-based graphical user interface. Multiple virtual servers can be built on a single control server.
Hardware virtualization improves the flexibility of server systems since any of the components in a virtual server can easily be replaced. For example, if a slower processing server in a virtual server is to be replaced by a faster processing server from the pool of processing servers, the control server can simply be set so that the disk and network interface that formerly communicated with the slower processing server communicate with the faster processing server instead. No physical replacement of components is necessary.